relational databases set the commercial data processing industry back at least ten years and wasted many of the billions of dollars that were spent on data processing. And, Computing history will consider the past 20 years as a kind of Dark Ages of commercial data processing.

relational databases performed a task that didn't need doing; e.g., these databases were orders of magnitude slower than the "flat files" they replaced, and they could not begin to handle the requirements of real-time transaction systems